Diversity and function in microbial mats from the Lucky Strike hydrothermal vent field

Area of Science:

• Microbiology
• Marine Biology
• Geochemistry

Background:

• Microbial mats are key primary producers in deep-sea hydrothermal vent ecosystems.
• Understanding microbial diversity and function is crucial for comprehending these unique environments.
• The Lucky Strike hydrothermal vent field is a significant Mid-Atlantic Ridge ecosystem.

Purpose of the Study:

• To investigate the diversity and function of microbial mats at the Lucky Strike hydrothermal vent field.
• To analyze the relationships between microbial communities and Bathymodiolus azoricus mussel symbionts.
• To identify key microbial groups involved in carbon, methane, and sulfur cycling.

Main Methods:

• Molecular approaches including DNA and RNA extraction from mat samples.
• Construction and analysis of 16S rRNA gene and functional gene libraries (RuBisCO, aclB, pmoA, aprA, soxB).
• Application of domain-specific 16S rRNA gene primers for Bathymodiolus symbionts and PCR/RT-PCR.

Main Results:

• Archaeal sequences were dominated by marine group 1 Thaumarchaeota.
• Bacterial sequences showed high diversity, with Proteobacteria and Bacteroidetes dominant; Beggiatoa (Gammaproteobacteria) was the dominant active population.
• Functional gene analyses revealed a diverse and active chemolithoautotrophic community, including symbionts of hydrothermal fauna, with evidence of methanotrophic and thiotrophic endosymbionts in mussels.

Conclusions:

• Microbial mats at Lucky Strike harbor a complex and active microbial community involved in key biogeochemical processes.
• Gammaproteobacteria, including Beggiatoa, play a significant role in the active microbial populations.
• The study highlights the intricate associations between microbial communities and vent fauna, particularly Bathymodiolus mussels, through shared metabolic pathways.